[ChrisMT79]

Hello all! Well it has been quite some time since I have looked into upgrading, or modifying stereo components of any sort in a vehicle in ages for me. And I am talking, senior year of high school, two 12 inch subs with some crazy amp rattle my car to pieces long time ago lol...
I plan to keep this car for quite some time, and even though I opted for the upgraded HK system, it does leave a bit to be desired in the low frequency/bass department. Now I am getting older, and years of wear and tear has taken its toll. I do not want anything intrusive to the outside environment. Just a nice low rumble to compliment the existing setup, while also being able to be installed with a custom box small enough that it is basically non-intrusive to the small trunk space we have (I have a F80 M3).
So any recommendations or guidance would be greatly appreciated!
Thank you in advance,
Chris